Three-dimensional printing-based additive manufacturing has emerged as a new frontier in materials science, with applications in the production of functionalized polymeric-based hybrid composites for various applications. In this work, a novel conceptual design was conceived in which an AC electric field was integrated into a commercial 3D printer (-based fused filament fabrication (FFF) working principle) to in situ manufacture hybrid composites having aligned ceramic filler particles. For this work, the thermoplastic poly lactic acid (PLA) was used as a polymer matrix while 10 vol% KNLN (K0.485Na0.485Li0.03NbO3) ceramic particles were chosen as a filler material. The degree of alignment of the ceramic powders depended upon print speed, printing temperature and distance between electrodes. At 210 °C and a 1 kV/mm applied electric field, printed samples showed nearly complete alignment of ceramic particles in the PLA matrix. This research shows that incorporating electric field sources into 3D printing processes would result in in situ ceramic particle alignment while preserving the other benefits of 3D printing.

Highly flexible lead free composite film having random distribution of ceramic filler was synthesized using Barium Titanate (BT) as a filler and inexpensive Thermoplastic Polyurethane (TPU) as a matrix. The results show that the 30 vol% BT-TPU composite has a dielectric constant of ~31 which is comparable to the expensive and difficult to produce PVDF based composites. With a breakdown field of 150 kV/mm, an energy density value of ~3 J/cm³ was estimated. These lead-free TPU based composites provide an alternative to PVDF based composites for energy storage applications.

A Li₄WO₅ ceramic with rock salt structure was prepared by the solid-state reaction method and its microwave dielectric properties was demonstrated for the first time. It could be well densified at relatively low sintering temperature (~890°C). XRD and DTA analysis revealed a phase transformation from cubic to orthorhombic occured at 700°C. Excellent microwave dielectric properties with a near-zero temperature coefficient of resonant frequency ~-2.6ppm/°C, a relative permittivity ~8.6 and a quality factor ~23,100GHz (at 11.0GHz) was obtained. Li₄WO₅ was found to be chemically compatible with silver powders when sintered at 890°C. All the results indicate that the Li₄WO₅ ceramic is a promising candidate as a base material in low temperature cofired ceramic technology.

A Ca₅Ni₄(VO₄)₆ low loss microwave dielectric ceramic with A site deficient garnet structure was prepared via the conventional solid state reaction method. Ca₅Ni₄(VO₄)₆ sintered at 980°C for 4h to a relative density of 96.2% exhibits favorable microwave dielectric properties such as a permittivity of 10.9, a Q×f value of 96,500GHz, and a τ _f value of -63.6ppm/°C. Its large negative τ _f could be compensated by forming a solid solution with LiCa₂Mg₂V₃O₁₂, that led to improved properties with a near-zero τ _f =-3.7ppm/°C, ε _r =10.2, Q×f=59,300GHz for 0.8Ca₅Ni₄(VO₄)₆-0.2LiCa₂Mg₂V₃O₁₂ after sintering at 955°C for 4h. Further on, 0.8Ca₅Ni₄(VO₄)₆-0.2LiCa₂Mg₂V₃O₁₂ proved to be chemically compatible with Ag electrodes, so it might be a possible candidate for LTCC applications.